Recurrent oncogenic ZC3H18 mutations stabilize endogenous retroviral RNA.

Area of Science:

• Molecular Biology
• Cancer Research
• Genetics

Background:

• Endogenous retroviral (ERV) RNA is highly expressed in cancer, but its role and the underlying molecular mechanisms are unclear.
• ZC3H18 (Z18) is a nuclear RNA surveillance complex component with recurrent truncating mutations observed in cancer.
• The oncogenic potential and specific functions of Z18 mutations in cancer remain largely unknown.

Purpose of the Study:

• To investigate the role of ZC3H18 (Z18) mutations in cancer development.
• To determine the molecular mechanisms by which Z18 mutations affect endogenous retroviral (ERV) RNA levels.
• To establish whether ERV RNA accumulation can functionally contribute to oncogenesis.

Main Methods:

• Analysis of ZC3H18 (Z18) mutations in cancer patient data and cell lines.
• Functional studies in zebrafish models to assess the impact of Z18 mutations on melanoma onset and ERV RNA levels.
• In vitro experiments using engineered human melanoma cells to examine Z18's interaction with ERV RNA.
• Zebrafish oncogenesis models to test the functional role of ERV RNA expression.

Main Results:

• Recurrent truncating mutations in ZC3H18 (Z18) were identified in cancer, and these mutations were found to be oncogenic.
• Z18 mutations lead to increased accumulation of endogenous retroviral (ERV) RNA in both zebrafish and human cancer cell lines.
• Z18 mutations exhibit dominant-negative activity, directly binding and stabilizing ERV RNA.
• Expression of ERV RNA alone was sufficient to accelerate oncogenesis in a zebrafish model.

Conclusions:

• ZC3H18 (Z18) mutations disrupt nuclear RNA surveillance, causing oncogenic ERV RNA accumulation.
• Aberrant accumulation of ERV RNA is a functionally significant driver of cancer development.
• This study reveals a novel mechanism linking Z18 mutations, ERV RNA dysregulation, and oncogenesis.